1. Field
Embodiments of the present invention relate to systems and methods for reducing engine emissions in a diesel engine, such as a locomotive diesel engine.
2. Description of Related Art
Locomotive manufacturers and remanufacturers supply locomotive diesel engines to the rail transportation industry, which includes establishments furnishing transportation by line-haul railroad, as well as switching and terminal establishments. In recent years, Environmental Protection Agency (EPA) emissions standards for locomotive diesel engines have become increasingly demanding. In particular, standards enacted under the Federal Clean Air Act of 1998 require significant reductions of individual emission compounds, including oxides of nitrogen (NOx). NOx gases, which include the compounds nitrogen oxide (NO) and nitrogen dioxide (NO2), are a major component of smog and acid rain.
Exhaust from a locomotive diesel engine includes various gaseous constituents, such as NOx, carbon monoxide (CO), carbon dioxide (CO2), and hydrocarbons (HC), as well as particulate matter. Severe environmental and economic consequences may ensue if locomotive engine emissions do not comply with applicable EPA standards.
U.S. Pat. No. 6,470,844 to Biess et al. discloses a system and method that automatically shuts down a primary engine of a locomotive after the primary engine has been idling for a predetermined period of time. A small secondary engine is started to perform useful functions on behalf of the shut-down primary engine. Because it reduces locomotive idle time, this approach reduces engine emissions. However, engine emissions remain a cause for concern when the primary engine is running.
Therefore, what is needed is a system and method for reducing engine emissions in a locomotive.